The present invention is an improvement over that disclosed and claimed in my U.S. Pat. No. 5,486,195 dated Jan. 23, 1996, the substance of which is incorporated hereinto by reference.
This invention relates to the sealing of a vascular puncture site. In particular, this invention relates to material and apparatus capable of facilitating the rapid sealing of an arterial puncture site using an energy sensitive, naturally occurring or synthetic (or a combination of both) sealant composition. The invention finds particular application to closure of an anterior arteriotomy site in a patient.
During approximately the 1940's, the Seldinger technique of percutaneous entry into a vascular structure by use of a needle and a guidewire technique was introduced to modern medicine and has subsequently become the standard in the medical industry. Prior to Seldinger's discovery of his technique for entry into vascular structures, procedures required an incision through the skin and tissues, commonly followed by an incision into the artery wall.
These earlier techniques had numerous associated problems, such as for example, infection, uncontrolled bleeding, trauma to the tissue and vascular wall, and others. Thus, the advent of the Seldinger technique was widely and rapidly accepted by the medical profession and it became the world standard due to its advantages to both patient and doctor. The patient benefited by less trauma, reduced risk of uncontrolled bleeding and vessel clotting, along with greatly reduced risk to infection. Doctors benefited by the ease of entry and exit in the procedure.
Seldinger's technique does not require suturing the artery puncture site or the skin and adjacent tissue as required in earlier procedures. Over the past 50 years, Seldinger's technique has remained virtually unchanged, its many advantages far outweighing the main or primary disadvantage, namely the sealing of the arterial puncture site. Using Seldinger's technique in order to seal the arterial puncture site, it is necessary to apply strong pressure to compress the arterial wall sufficiently to reduce blood flow and intraluminal pressure to allow initiation of the body's own hemostatic processes. Typically, compression takes between 45 minutes to one hour before closure of the arteriotomy by natural clotting. Thereafter, inactivity with bed rest is required for a period of from 8 to 12 hours to allow the clot to strengthen. The patient often cannot return to normal activity for periods of up to two to three days following arteriotomy procedure.
The medical, social and economic impact of this prolonged recovery period is substantial. In fact, with over three million arteriotomy procedures undertaken annually in just the United States, the prolonged recovery period of Seldinger's technique has an economic impact of billions of dollars incurred through additional hospital stay costs alone. Therefore, a need exists to develop a safe and effective means for effectively and expeditiously sealing the arterial wall following arteriotomy procedures which allows the patient to quickly return to normal activity.
Current procedures to seal the arteriotomy site normally consist of a direct surgical suture closure or the application of sufficient external pressure so as to exceed the fluid pressure existing within the vascular structure, thus eliminating seepage through the arteriotomy site, permitting the body's clotting system sufficient time to form a clot to seal off the arteriotomy site.
New technology emphasizing the application of a non-human, pre-formed collagen plug has demonstrated significant effectiveness. However, the long and short term effects of routinely implanting such foreign materials are of concern and remain unknown.
Additionally, in recognition of the dangers posed when entering the vascular lumen, much emphasis has been placed on developing a delivery system which measures the distance from the skin to the puncture site. In one procedure, a biodegradable suture material anchor is actually sunk through the vascular wall and into the lumen in an attempt to obtain a snug fit of the collagen plug, with the plug being pulled down over a piece of suture towards the arterial puncture site. This step introduces an additional foreign substance into the lumen at the arteriotomy site. Other techniques use a percutaneous technique of closing the arteriotomy site with sutures being introduced from the outside to the inside of the artery. Still another technology uses a similar percutaneous technique but sutures the artery from the inside to the outside.
The main difficulty, however, is that most cardiologists are neither familiar with nor are they comfortable with suturing arteries. This was not the case 20 years ago, but in the past 20 years, suture closure of an arteriotomy site has become rare. Another difficulty arises in that the technologies that try to advance a collagen plug towards the artery, do so without debriding the anterior arterial wall, and thus the plug never contacts the anterior arterial wall surface in juxtaposition to the arteriotomy. Thus, this system or technique permits body seepage to continue to occur between the anterior arteriotomy area and the bottom of the plug when the plug has failed to reach the actual wall surface.
The objective of all these techniques has been to eliminate the 6 to 24 hour bedtime requirement when simple external pressure has been used to obtain closure of the arteriotomy site. Immediate sealing of the arteriotomy site by proper use of a plug technique dramatically facilitates early ambulation of the patient, thus eliminating medical, social and financial costs associated with the above.
In an effort to preserve the effectiveness of the plug technique and to further maximize patient safety, another device and technique was developed permitting debridement of the anterior arterial wall and the use of a sealant such as a fibrin glue. In the device used in this technique, tandem balloons are located such that the distal balloon, when inflated, occludes the intraluminal arteriotomy site. A second external balloon inflates over the anterior arterial wall debriding the tissue and creating a cavity beneath the balloon, permitting the injection of a two-component fibrin glue (beef thrombin) and fibrinogen derived either from cryoprecipitate or autologous fibrinogen. When these two substances come into contact one with the other and additional materials such as calcium and apoprotein are added, a rapidly hardening sealant is formed which attaches to the debrided anterior arterial wall in juxtaposition to the arteriotomy site. As gelling commences, the distal balloon within the arterial lumen is deflated and pulled back through the gelatinous material, with the external balloon being permitted to remain in place until the glue fully hardens and becomes attached to the area adjacent the arteriotomy and within the anterior arteriotomy site. In those situations where anticoagulants have been administered before commencing the procedure and the normal in-vivo clotting mechanisms are altered, this latter device would function to accommodate such a situation. By way of explanation, once the fibrinogen and fibrin have been combined and adhere to the area adjacent to the anterior arteriotomy site, anticlotting agents have no significant effect on the plug.
There are difficulties experienced with the above-described technology and procedure, and certain of them are as follows:
1. One must inject the glue as two separate components so that the injected components do not come into contact, one with the other, so as to "set up" in the lumen through which they are injected. PA1 2. The necessity of keeping the two components separate from one another results in incomplete mixture at the arteriotomy site and significantly reduces the strength and effectiveness of the resultant glue blend. PA1 3. One must carefully coordinate the pullback of a distal balloon through the glue while it is in the process of setting up so as to wait sufficiently long so that the glue becomes sufficiently set and cannot enter the lumen of the artery, and yet not so long that the glue becomes "set up" to the extent that difficulties are created in pulling the balloon through the gelling or gelled substance. PA1 4. There is significant unpredictability to the concentrations of the glue formulations so that the rate at which gelling occurs depends on a number of variables which are difficult to control and/or determine. Among these are the amounts of calcium, apoprotein and other chemical substances released by the disrupted tissues.
Additionally, there are immunological and infectious complications associated with the present FDA-approved glue components (bovine thrombin) and human-pooled cryoprecipitate (the source of fibrinogen) Immunological studies have demonstrated a high incidence (11 of 24 patients) of antibodies to bovine thrombin, resulting in the development of thrombin and factor V inhibitors. The latter is felt to be associated with factor V contaminant in the FDA-approved bovine thrombin. These antibodies may cross-react with human coagulation factors, particularly factor V, resulting in clinical bleeding. Infectious concerns about the FDA-approved source for fibrinogen surround the possible contamination of hepatitis A, B and C and the human immunodeficiency virus (HIV).
To overcome the immunological and infectious concerns, the sealant industry has developed promising new technologies. Pooled human thrombin and fibrinogen can now be treated by a solvent detergent technique, which eliminates the lipid-laden, enveloped viruses including hepatitis B, hepatitus C, and the HIV virus. Pasteurization eliminates hepatitus A. Thus, the immunological and infectious concerns can be eliminated. In addition, novel synthetic, ultraviolet (UV) light sensitive, biogradable polymers such as polycaprolactone have been developed as efficient sealants.
Recognizing that the application of thoroughly mixed sealant in a fine, evenly distributed manner is critical to hemostasis at the arteriotomy site, technologies have recently been developed which render the thrombin inert and energy sensitive, such that the thrombin and fibrinogen can be thoroughly mixed in vitro without reacting until a specific energy source, such as ultraviolet light, visible light, or laser energy is applied.
Therefore, there still exists a need for a method and apparatus to deliver and evaluate a controlled sealing agent to an arteriotomy site.